From Fr. Walsh's History of the Irish Hierarchy, (1854), at pages 246 and following:
DIOCESE OF CLOYNE AND ROSS
The first of these sees was founded by Saint Colman about the year 580. Colman was of royal extraction by his father's side whose name was Lenine or Lenin and brother to one of the Saints Bridget. He is sometimes surnamed Mitine, whence it is to be inferred that he was a native of the district called Muskerry in the county of Cork. The time of his birth is not known but it was probably about the year 522. He seems to have devoted his early years to the study of poetry and we are assured that he was domestic poet to the prince Aodh Caomh, who was raised to the throne of Cashel about the middle of the sixth century, and that he was present, together with Brendan of Clonfert, at his inauguration in Maghfemyn between Cashel and Clonmel. Colman soon after, in accordance with the advice of Saint Brendan, renounced his worldly pursuits and is said to have repaired to the school of St Jarlath at Tuam. Some say that he was the disciple of St. Finbarr of Cork but it is not likely as Colman must have been much older. Colman died according to some in the year 601 or to others in 604. His festival is marked at the 24th of November. It appears that St. Colman became an eminent scholar as he has left a life of St. Senan of Inniscathy written in Irish metre and in an elegant style. He was also a great proficient in the science of the saints.
[Another account of St. Colman's life is to be found here.]